The invention relates to a paraglider which flies by the lift force of a collapsible airfoil. As those skilled in the art are aware a paraglider airfoil is formed and maintained in its inflated stated by air entering as the paraglider moves forwardly in flight.
The canopy of a conventional paraglider is made of a non-porous cloth material and is divided into a number of separate, parallel air chambers by vertical ribs. The front is generally is open to form an air intake opening. Air enters each chamber through the front air intake opening and inflates the canopy. In cross section the canopy resembles an airplane wing to provide an airfoil configuration. The paraglider canopy is maintained in its inflated state by its forward flight movement inducing air pressure inside the chambers.
Like an airplane wing, air flowing over both surfaces of the airfoil exerts an upward force or lift and thus the device can glide through air. Paragliders of the type described are well known and in use.
So long as the glider maintains its forward speed using natural winds and air currents it is well able to fly.
A canopy that is made of non-porous cloth which is both soft and flexible can be folded or compacted into a relatively small bundle or mass. Thus it is convenient to carry and to stow away.
Air entering the front air intake openings inflates the canopy with sufficient pressure to maintain the canopy's shape.
Some currently known gliding paragliders utilize plastic reinforced cloth materials to prevent collapse of the air intake openings since it will be appreciated that it is important to maintain the air intakes fully opened so that the canopy itself retains its shape. Even partial loss of airfoil configuration can result in loss of glide capability.
Construction of a paraglider with reinforcing material, however, involves the possible risk that the airfoil will collapse because of differences in weight and hardness between the plastic materials and the cloth.
Conventional paragliders made without reinforcing material have a disadvantage in that if the canopy airfoil at least partially collapses it loses air pressure within the canopy chambers. Accordingly, if the canopy cannot maintain its shape because of loss of air pressure inside, then the canopy loses its lift capability, particularly in strong turbulence and winds.
Slowing the forward speed of a paraglider makes it difficult to maintain sufficient ram pressure to keep the airfoil inflated. It will be understood then that the canopy inflation is maintained by forward movement. Slowing forward movement may also cause the canopy to deflate and collapse completely.
Once an air intake opening has lost shape so that the air intake opening is smaller and irregular, ram air pressure is so reduced that the canopy actually acts as a brake. In this situation of course the pilot or operator is in danger of falling. In this circumstance and in order to recover flight capability of the canopy airfoil configuration, it is necessary to undertake a risky maneuver. The pilot or operator must initiate a rapid loss of altitude or quick drop to generate pressure to reestablish air worthiness. While the maneuver may create the necessary air pressure for recovery of flight it may also face the pilot with a crash problem.